The broad objective of this research proposal is to determine the electrophysiological processes which regulate motility of the smooth muscle cells of the antrum, fundus and gastric sling muscle of human and canine stomach. The areas of particular interest are: (a) mechanism of action and interaction of the gastrointestinal hormones secretin, cholecystokinin, motilin and the family of gastrins, (b) the way in which the gastric action potential in the antrum regulates the motor action of these hormones, (c) the ionic basis of the gastric action potential and of the action of gastrointestinal hormones, (d) the electrophysiological characteristics of the fundus and gastric sling muscle, and (e) the motor and electrical effect of the above mentioned hormones on fundic and gastric sling muscle. The methods of approach will be measurement of motor activity of strips of muscle, measurement of electrical activity of single smooth muscle cells using the intracellular technique and measurements of electrical activity of bundles of smooth muscle cells using the double sucrose gap technique.